8.E.2- Earth History
Unit Topic
Earth History
Essential Standards Goals
and Objectives
Standard 8.E.2 Understand the history of Earth and its life forms based on
evidence of change recorded in fossil records and landforms.
8.E.2.1 Infer the age of Earth and relative age of rocks and fossils from index
fossils and ordering of rock layers (relative dating and radioactive dating).
8.E.2.2 Explain the use of fossils, ice cores, composition of sedimentary rocks,
faults, and igneous rock formations found in rock layers as evidence of the
history of the Earth and its changing life forms.
Concepts Being Studied
Relative dating, absolute dating, index fossils, geologic column, geological and
biological evolution, rock disturbances and unconformities
Relative dating= rock layers on top are younger than the layers below
absolute dating=using the radioactive decay of elements to find the precise age
of a rock layer or fossil
index fossils= fossil remains of an organism that lived all over the earth for a
short period of time, therefore you can identify the age of the rock layer by
identifying the index fossil
geologic column= layers of rock
geological and biological evolution= change of the earth and living things over
time
rock disturbances= ways that the geologic column can be changed including
faults, folding, tilting, intrusions, and unconformities
unconformities= missing time periods in a geologic column due to the lack of
sediment deposition or erosion.
classify, climate, conifer , crust, crystal, decay, decompose, deposit, dinosaur,
Earth, environment, epoch, era, evolve, extinct, fauna, fish, flora, flowering
plant, fossil, habitat, herbivore, igneous rock, index fossil, insect, invertebrate,
limestone, mammal, marine, mass extinction, microorganism, multi cellular,
omnivore, organism, period, pollen , population, predator, prehistoric, reptile,
rock cycle, rock layer, sediment, sedimentary rock, skeleton, species, spinal
cord, spine, survive, tectonic plate, unconformity, vertebrate, volcano, warmblooded
strata, stratum, relative dating, absolute dating, isotope, radioactivity,
radioactive decay, half-life, cross-cutting relationship, uniformitarianism,
geologic time, superposition
Essential Questions
Fossils and Studying Earth's Past
What is a fossil?
Answer: Fossils are the remains or traces of ancient living things preserved in
rock or sediment.
How do fossils show how organisms have evolved through time?
Answer: Some changes in physical features of organisms can be seen in fossils
of related organisms. These fossils can be dated according to their position in
the geologic record and this makes it possible to map out these changes in
physical features over time.
How do fossils provide evidence of environmental changes that occurred in the
past?
Answer: Each type of living thing must live in a certain environment to survive.
If fossils of that species are found in a rock layer, this provides evidence that the
environment at the time enabled it to survive. So by studying fossils from
different time periods, scientists can then infer how environments changed over
time.
What are the different types of divisions of geologic time?
Answer: Eras are the longest division of geologic time. Eras are divided into
periods, which are then divided into epochs.
How do the ages of the oldest fossils compare to the age of Earth?
Answer: The oldest fossils known are about 3.5 billion years old. Earth is about
4.6 billion years old. There may have been no life on Earth for its first one
billion years of history.
Formation of the Earth
What evidence can scientists use to study Earth's history?
Answer: Scientists can interpret the history of Earth by studying rocks and the
fossils preserved within them, sometimes called the rock record. The rock
record was created by the same processes that are part of the rock cycle today,
such as weathering and erosion, plate tectonics, and volcanic activity.
Therefore, scientists can use what they observe today to interpret what
happened in Earth's past. For example, if scientists find fossils of marine
animals on top of a mountain peak, they can infer that the rock that makes up
the mountain used to be at the bottom of an ocean. Scientists can also study the
ages of rocks in the rock record to interpret the age of Earth.
What methods do scientists use to determine the ages of rocks?
Answer: Scientist can determine the ages of rocks using absolute dating and
relative dating methods. Absolute dating is based on radioactive elements in a
rock and can be used to determine how old a rock is in years (usually millions
of years). Relative dating can be used to determine the ages of layered rocks
compared to each other. Relative dating does not provide the actual age in years
of a rock. Rather, it describes whether a particular rock layer is younger or older
than the other layers.
How are geologic principles applied to understanding Earth's history?
Answer: Over time, scientists have developed geologic principles that describe
the way Earth formed and how it changes over time. They use these principles
to determine relative ages of layered rock and to interpret how rocks formed
and have been altered. One theory, the Theory of Uniformitarianism, explains
that Earth has changed gradually over time, rather than in short bursts. It also
explains that the same geologic processes that occurred in the past also occur in
the present. Therefore, we can use what we see today to interpret what
happened in the past. If rocks have been folded or tilted, scientists can use
geologic principles to determine which rocks are older and younger even if the
layers have moved. Scientists also use the same methods based on fossils that
occur in different layers.
What can you infer from a geologic column about the history of the earth?
Essential Information
8.P .2.1 Different ways of obtaining, transforming, and distributing energy have
different environmental consequences. Different types of fuels have different
environmental impacts. Some have longer lasting impacts on the environment
than others. Transformations and transfers of energy within a system usually
result in some energy escaping into its surrounding environment. Some systems
transfer less energy to their environment than others during these
transformations and transfers. Whenever energy appears in one place, it must
have moved from another. Whenever energy appears to be ‘lost’ from
somewhere, it has been transferred somewhere else. Some ways we are
attempting to use the energy from the sun are: photovoltaic cells, solar batteries
and reflectors. Photovoltaic cells transform solar energy into electric energy.
Solar reflectors are used to concentrate solar rays for industrial use and for the
generation of electric current. One way to confine the solar energy is heating
water by passing it through collectors and keeping it in isolated containers. In
some cases it is possible to obtain enough hot water to satisfy a house needs
during the day but conventional heaters are required at night. Energy from the
sun far exceeds the Earth’s energy need, however, we have not found a way to
efficiently capture and store it.
8.P .2.2 Some resources are not renewable or renew very slowly. Fuels already
accumulated in the earth, for instance, will become more difficult to obtain as
the most readily available resources run out. How long the resources will last,
however, is difficult to predict. The preservation, management, and care of
natural and cultural resources should be practice by all consumers. The ultimate
limit may be the prohibitive cost of obtaining them. Energy from the sun (and
the wind and water energy derived from it) is available indefinitely. The
transfer of energy from these resources are weak and variable, systems are
needed to collect, transport and concentrate the energy. This creates some
advantages and disadvantages depending on location and the ability to collect.
Essay Questions
Look at an example of a disturbed geologic column. Describe the history of
that column using evidence found from the picture. Make sure to include and
define the following terms: Relative dating, index fossils, geologic column,
geological and biological evolution, rock disturbances and unconformities
Project Ideas
Prezi project on geologic time period
Time travel brochure on a time period
Technology
Prezi on fossils
Techbook resources
Power Point for geologic column and disturbances
Student Prezis on geologic time period
Labs, Experiments,
Activities, etc.
Peanut butter and jelly geologic column lab- cut up to make faults
Candium lab- showing absolute dating of M&M’s.
http://www.kwanga.net/chemnotes/candium-lab.pdf
Sea floor spreading lab- made a model sea floor out of paper with different
colored paper showing rock layers
Geologic Time adding machine tape model- in Foss Kit
Hands-on activity: Geologic Time in the techbook. In this activity they scale
geologic time to their height, calculating the amount of their bodies that
represent each part of geologic time.
Mold and Cast plaster of Paris lab
Fossil find using sediment from quarry- Lee’s QuarrySeries of rock identification and rock column building labs from the grand
canyon, in the earth history kit
Principle of Superposition: gather pictures of you from different ages and stack
them oldest to newest and demo to class. Also, describe a messy student’s
locker as having oldest missing assignments on the bottom and newer towards
the top
Resources
Techbook
Earth History Kit
Assessment
Projects
Laboratory write-ups
Essay
Test
Informal Observation
Exit slips
ClassScape
EOG